Projection Lens with Reflecting Group for Aberration Control
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Solution Overview
Problem
Current wide-angle projection lenses face challenges in reducing aberration while maintaining high imaging quality, small size, and low manufacturing costs, as existing solutions either increase lens length or use multiple lenses, which are costly and inefficient in mass production.
Innovation Solution
A projection lens design comprising a first lens group, a second lens group with an aperture stop, and a reflecting lens group with a curved surface, which reduces overall volume and manufacturing costs by compensating for image distortion and optimizing lens configuration to achieve high imaging quality and a wide-angle field of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple aspheric lenses are used to correct aberration, then imaging quality is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The lens system is divided into three distinct lens groups (first lens group with positive refractive power, second lens group with positive refractive power and aperture stop, and reflecting lens group with negative reflecting power). This segmentation allows each group to perform specific functions: the first group handles initial light convergence, the second group controls aberration and field of view, and the reflecting group corrects wide-angle distortion. By dividing the complex correction task into modular groups, the design achieves high imaging quality without requiring excessive individual lens elements.
Solution Approach 2:
The aperture stop positioned between the lenses of the second lens group serves as an intermediary element that controls the field of view and helps manage aberrations. The reflecting lens group acts as an intermediary that reflects and redirects the image light beam to compensate for wide-angle projection distortions. These intermediary elements enable the system to achieve complex optical correction without proportionally increasing the number of main lens elements.
2Manufacturing precision
If the length of the projection lens is increased to reduce aberration, then imaging quality is improved, but the overall volume increases
Solution Approach 1:
The reflecting lens group introduces a reflective dimension to the optical path, allowing light to be redirected through a different spatial dimension rather than simply extending the linear path length. By using reflection to compensate for wide-angle distortion, the system achieves aberration correction without proportionally increasing the axial length of the lens system, thus maintaining a compact overall volume.
Solution Approach 2:
The design changes the optical parameters by introducing a reflecting lens group with negative reflecting power, which has a different optical function compared to traditional refractive lenses. This parameter change allows the system to achieve aberration correction through a different optical mechanism (reflection rather than only refraction), enabling compact lens length while maintaining high imaging quality.
3Manufacturing precision
If more number of lenses are used to correct aberration, then imaging quality is improved, but manufacturing cost increases
Solution Approach 1:
The lens system is segmented into three functional groups with specific roles: the first lens group for initial convergence, the second lens group for aberration control and field of view management, and the reflecting lens group for distortion correction. This segmentation allows the design to achieve high projection quality through coordinated action of the groups rather than using a large number of individual lenses, thereby reducing manufacturing cost.
Solution Approach 2:
The design replaces some refractive lens elements with a reflecting lens group that uses reflection to achieve distortion correction. This substitution reduces the total number of refractive lens elements needed, as the reflecting group can compensate for wide-angle projection distortions that would otherwise require multiple additional refractive lenses, thereby lowering manufacturing cost.
4Productivity
If a wide-angle projection lens is used to shorten projection distance, then productivity is improved, but aberration increases
Solution Approach 1:
The reflecting lens group acts as an intermediary that specifically addresses the aberration problem introduced by wide-angle projection. By reflecting and redirecting the image light beam with negative reflecting power, it compensates for the distortion and aberration caused by the wide-angle field of view, allowing the system to maintain short projection distance while correcting the resulting optical imperfections.
Solution Approach 2:
The design changes the optical parameter by introducing a reflecting lens group with negative reflecting power to counterbalance the wide-angle projection effects. This parameter change enables the system to maintain a short projection distance (high productivity) while the reflecting group corrects the aberration through its negative reflecting power, achieving both goals simultaneously.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design effectively reduces the overall volume and manufacturing costs of the projection lens while maintaining high imaging quality by utilizing a reflecting lens group to compensate for wide-angle projection distortions, allowing for a smaller and more cost-effective lens configuration.
Implementation Method 1
The first lens group has positive refractive power
Implementation Method 2
The second lens group has positive refractive power
Implementation Method 3
The reflecting lens group has negative reflecting power and is located at a side of the second lens group far away from the first lens group. The reflecting lens group has a curved reflecting surface to reflect the image light beam passed through the second lens group
Data Source
AI summary
A projection lens for a projection device having a light valve is provided. The light valve provides an image light beam. The projection lens includes a first lens group, a second lens group and a reflecting lens group. The second lens group is disposed between the first lens group and the reflecting lens group. The first lens group has positive refractive power. The second lens group has positive refractive power and includes a plurality of lenses and an aperture stop located between the lenses. An angle of a field of view of the second lens group is less than 100 degrees. The reflecting lens has negative reflective power and has a curved reflecting surface to reflect the image light beam passed through the second lens group.